Computing does not have to rely entirely on transistors. Biological computing uses biological components to represent and process information. The term covers several approaches, including DNA reactions, engineered cellular circuits and networks of living neurons. Their physical or chemical activity participates in the computation itself.
In a molecular circuit, the presence of a particular sequence can trigger a reaction that produces an output signal. Combining reactions enables logical operations. Writing a file into DNA and preserving it, by contrast, is storage and does not necessarily constitute computation. Neural tissue experiments face a different challenge: providing inputs and obtaining reproducible, interpretable responses.
Potential uses include biosensing and information processing within cellular environments. Reaction speed, environmental requirements, stability and readout remain substantial constraints. These are research systems rather than replacements for personal computers. Organoid intelligence belongs within this broader landscape, but a DNA circuit is not a brain, and information processing in tissue does not itself demonstrate consciousness.